Electronic devices, such as computers, mobile phones, personal media players (PMP), gaming consoles, or other electronic devices typically require a user interface for a user to interact with the devices. Touch-sensitive screens (“touch screens”) are one type of user interface that allows a user to interact with the device by physically making contact with the device. In one example, a user may touch the screen of a mobile device to initiate execution of an application stored on the mobile device. Some techniques employed in these devices for detecting the location of a touch include mechanical buttons, crossed beams of infra red light, acoustic surface waves, capacitive sensing, and resistive sensing techniques.
Certain touch screens may be designed to simultaneously recognize touches at more than one point on the screen, a feature commonly referred to as “multi-touch.” Multi-touch screens separately identify and interpret touches in different areas of the screen. Simultaneously touching a multi-touch screen in more than one location may provide a user with additional ways to interact with the device (e.g., versus a single touch).